Cannulated modular intramedullary nail

ABSTRACT

A modular intramedullary nail includes three connectable sections that are connectable end to end. The three sections include an upper proximal nail component having an open ended bore. The second section is a central nail section that is an elongated curved nail component having an open ended longitudinal bore. The third section is a lower distal nail component having an elongated open ended longitudinal bore. The nail components are connected and the end using corresponding conical socket and conical projecting end portions of adjoining end nail components that can be fitted together and secured upon impact. Upon assembly, the connections are self orienting, providing corresponding tooled &#34;flat&#34; portions adjacent the respective conical socket and conical projecting end portions of the nail components. This interlocking tooled flats align and abut upon assembly so that the adjoining nail components only align in one relative rotational position. The assembled nail thus provides an elongated continuous open ended bore that receives a cannulated fastener. The fastener extends the full length of the longitudinal bore of the assembled three nail sections. An upper enlarged head portion of the cannulated fastener grips the proximal nail component. The distal end portion of the cannulated fastener has external threads which engage corresponding internal threads within the bore of the distal nail component.

SPECIFICATION

1. Field of the Invention

The present invention relates to an intramedullary nail system for therepair of long bone fractures, which has a modular design for enabling asurgeon to assemble a nail or related implant during surgery which mostclosely fits the patient's needs.

2. Background of the Invention

Intramedullary nails have become the preferred implant treatment in manylong bone fracture cases. As the use of intramedullary nails has becomemore popular, the design of the implants has advanced so that there areparticular designs for different types of fractures. Nails having aparticular configuration are desirable for certain indications. Becauseof wide variation of the long bones in patients, the particular style ofnail is preferably available in a range of lengths, diameters, andshapes. As a result, the surgeon must have at hand a large inventory ofstyles and sizes to accommodate the variety of indications. Examples ofsuch styles include, but are not limited to femoral reconstruction,intramedullary hip screw, and femur components of total femoral hips.

One solution to this variation problem is to provide a modular nailsystem where a surgeon can select various component parts and assemblethem to fit a particular patient's needs. Such a system is taught inU.S. Pat. No. 4,805,607 to Engelhardt et al. where a modularintramedullary nail system has elongated base nails and extensionmembers of different lengths and diameters. The base nail is the primarystructural component of the system and the extension member is designedto fit on the proximal end of a base nail. By selecting variouscombinations of base nails and extension members, nails of a desiredlength and diameter can be constructed. The component parts are lockedtogether by a pair of snap lock springs formed on the proximal end ofthe base nail, which include engagement tongs with locking barbs at thetrailing end which are radially depressed in order to engage acounterbore on the extension member. A screw is inserted through a holein the modular components after the rod has been implanted forpreventing the tongs from disengaging.

Another intramedullary nail is disclosed in the Simpson et al. U.S. Pat.No. 5,122,141, entitled "Modular Intramedullary Nail". In the Simpsonpatent, an intramedullary nail system and method for providing acapability of creating intramedullary nails of any desired lengthincludes a combination of a small number of base nail members adapted tobe joined to any one of a variety of hollow extension nail members. Anyselected extension nail member may be axially connected to any selectedbase nail member in order to prevent axially separation of the members.Additionally, each extension nail members provided with transverseopenings adapted to receive a bone screw to secure the intramedullarynail within the bone to be repaired. The extension nail member isinfinitely rotationally adjustable about the axis of the base nailmember in order to enable the fixation of the extension member with anydesired degree of anteversion prior to final assembly of the base nailmember with the extension nail member.

The Comte et al. U.S. Pat. No. 4,875,475 shows a device for treating abone that includes an intramedullary nail adapted to be driven into ahollow bone. The proximal terminal nail segment includes an internalthread and a transversely penetrating longitudinal slot adapted toreceive a screw to penetrate through the nail, and to be screw connectedto the bone. A distal terminal nail section comprises two transverselythroughgoing bores, each adapted to receive a screw to be screwconnected with the bone.

The Chapman et al. U.S. Pat. No. 4,776,330 discloses a modular femoralimplant system for use in the treatment of femoral disorders resultingfrom injury, disease, or congenital defects. The modular system includesat least three interconnected components, including an elongatedepiphyseal-metaphyseal implant, an intramedullary rod, and an angledside plate having an elongated plate portion adapted to be secured tothe outer cortical wall, and a hollow sleeve adapted to extend into thefemur.

A French Patent No. 1,031,128 relates to a femoral nail of multiplesections.

The Fischer U.S. Pat. No. 3,846,846 discloses a ball-shaped portion toform part of the hip joint and a second portion that extends from theball-shaped portion into the femur. The second portion is provided witha passage through which an elongated expander rod is extended which isalso to be inserted into an opening in the femur and on the expanded rodis arranged a series of expansion elements in the form of a row which asthe expander rod is moved longitudinally of the row are all expanded toanchor the prosthesis to the femur.

An adjustable compression bone screw is disclosed in the Glisson U.S.Pat. No. 4,858,601 that includes a shaft having first and secondsections each with an external thread that may be rotated as a unit orindependently. The screw includes means adapted to receive a firstdriving tool for driving the shaft as unit, and further adapted toreceive a second driving tool for rotating the second sectionindependently of the first section.

The Tronzo U.S. Pat. No. 4,940,467 discloses a variable length fixationdevice for insertion into a hole formed in two or more bone fragmentsand includes a barrel portion and a fastener element. The device is usedfor repair of the proximal portion of a patient's femur.

The Marcus U.S. Pat. No. 4,622,959, entitled "Multi Use FemoralIntramedullary Nail", discloses an intramedullary nail for use infractures for the left or right femur and includes a body having a head,an intermediate portion, and a distal tip. Transverse openings areprovided in the body near the distal tip and in the head for receivinglocking screws. One opening in the head has its axis within the femoralneck and another opening has its axis generally transverse thereto. Thenail head has a seat with a transverse locating slot for securing ascrew insertion tool in a fixed angular position in which the screwguide on the tool is aligned with one of the screw receiving openings.

The Brumfield U.S. Pat. No. 4,827,917 (incorporated herein byreference), entitled "Femoral Fracture Device," provides an apparatusfor treating fractures of the femur that includes a screw and anintramedullary rod. The screw has a threaded portion and a smoothportion. The rod has a head, stem, and longitudinal bore. There is atleast one pair of coaxial holes through the stem, transverse to thelongitudinal axis of the rod, for receiving first anchoring means suchas a nail, screw, or bolt, to secure the rod within the marrow canal ofthe femur. There are at least a proximal pair of coaxial holes and adistal pair of coaxial holes in the head of the rod in an angleddirection toward the femoral head relative to the longitudinal axis ofthe rod. The distal pair of head holes are adapted to slidingly receivethe screw to permit the threaded portion of the screw, in use, to engagethe femoral head and to allow sliding compression of a femoral neck orintertrochanteric fracture. An optional second anchoring means whichwill also allow sliding and compression and an optional set screw arealso provided to adapt the fracture device to a variety of applications.

U.S. Pat. No. 4,995,883, issued to DeMane et al. and U.S. Pat. No.5,108,452, issued to Thomas W. Fallin, both entitled "Modular HipProsthesis," disclose a modular hip prosthesis that can be custom fittedto a particular patient by a surgeon prior to surgical insertion. Theprosthesis features a body having a neck portion for carrying a roundedhead element, a transitional mid-section of the prosthesis body includesgenerally rectangular and generally rounded cross-sectional areas, and astem section has a generally rounded cross-sectional area. The stem istapered to receive a tubular extension sleeve with a hollowed portioncorresponding in shape to the stem portion of the prosthesis. Thetubular extension sleeve has an open end portion receptive of the lowertapering stem of the prosthesis body. The stem portion including aninternal bore, and an attachment in the form of an elongated screw isprovided for connection to the stem internal bore for securing theextension sleeve and the prosthesis body together, forming a compressivesealed connection therebetween. Pads can be attached to the transitionalmidsection of the prosthesis body for increasing the cross-sectionalshape of the prosthesis at the transitional midsection. Removablecollars can be added to the prosthesis to form a transverse loadcarrying interface with the upper end of the patient's femur.Frustroconically shaped extension sleeves can be added to the prosthesisneck for extending the neck length.

U.S. Pat. No. 5,047,033, issued to Thomas W. Fallin, entitled "Mill AndGuide Apparatus For Preparation Of A Hip Prosthesis," discloses a guideapparatus for preparing the femur of a patient with a rotary mill toreceive a femoral hip prosthesis includes a V-shaped guide body having alower end base portion adapted to extend into the intramedullary canalof the femur and an upper end portion comprised of at least two spacedapart struts so that the overall guide body had a configurationsubstantially the same as the prosthesis body sought to be implanted inthe patient. The lower end of the guide body base provides one or morehemispherical receptacles for holding the hemispherical end portion of aspinning mill bit. A preferably removable transverse guide rail hasconnection pins at one end portion thereof for forming a connection withthe upper end of the guide body at one of the struts, the arm having acurved surface that is adapted to guide the mill bit during preparationof the intramedullary canal of the patient's femur for receiving a hipprosthesis thereafter.

The inventors have determined it is advantageous to have a nail systemwith greater modularity than in a system such as shown in the Engelhardtpatent, and one providing an easier and more secure method of attachingthe components, which is assembled without utilizing a screw to hold thecomponents together. And a modular nail that can be driven over a guiderod.

SUMMARY OF THE INVENTION

The present invention is directed to improved intramedullary nailsproviding a modular intramedullary nail system having three modularcomponents. The components include proximal, central, and distal nailsections. The modular components of the present invention are quicklyand easily assembled having joints of high mechanical and torsionalintegrity.

The modular components of the present invention preferably include alocking mechanism for connecting and locking together adjacent modularcomponents which can quickly provide a positive locking fit that resistsrelative twisting or rotational movement between the components as wellas translation.

Assembly of the modular components of the present invention is achievedby one modular component having a socket with a conical tapered surfaceadapted to securely engage a cooperating tapered pin or projectingconical surface. The engagement results in a secure taper lock or wedgelock connection which is resistant to translational forces. An exampleof a modified taper and bore providing such secure connection is aconfiguration known as a morse taper.

Resistance to rotational movement between adjacent nail section isachieved by providing tooled "flats" adjacent each taper (i.e., a tooled"flat" on the conical socket of one nail section and a correspondingmating tooled "flat" on the engaging conical projection of an adjoiningnail section).

In a preferred embodiment, the tooled flats are prepositioned to providean alignment mechanism to ensure the components are properly assembledin a pre-selected position of anteversion.

A cannulated fastener extends the full length of the assembled nail. Thecannulated fastener has a longitudinal bore for tracking a guide wireduring installation.

The technique for intramedullary nailing is challenging and ispotentially dangerous. The location of the entry portal ultimatelydetermines the location of the locking screws, which is not critical inthe femoral mode but is very critical in the recon mode. The surface ofthe bone is angled and surrounded by muscles. Typical open incisiontechnique has a guide road in the muscles to locate the entry portal,which slips on the angled bone and the muscles make fine adjustment ofthe thin guide rod difficult and can be very time consuming, adding tothe time the patient must be under anesthesia. If the entry portal isoff of the optimal placement, the later portion of surgery, placement ofthe screws in the femoral head, gets very difficult and can be very timeconsuming and lead to poor outcomes.

The procedure is very bloody, especially the reaming of the canal. It isnot uncommon for the floor to have standing pools of blood and have thesurgical team splattered heavily. The risk of disease transfer is highand the cleaning costs are high also.

Many patients are obese and when in the position to have a femur nailedhave many inches of soft tissue on the lateral aspect of their thigh.The positioning of a conventional recon drill guide is difficult due tothis tissue and frequently the skin must be opened for the length of thedrill guide, about 8 inches, to allow the drill guide to be advanced tothe full depth.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to acquire a better understanding of the invention, referencemay be had to a detailed description of exemplary embodiments set forthbelow, to be considered along with the appended drawings, in which:

FIG. 1 is a side, partially exploded view of the preferred embodiment ofthe apparatus of the present invention;

FIG. 2 is a sectional view taken along lines 2-2 of cannulated fastener16 of FIG. 1;

FIG. 3 is an exploded side view of the preferred embodiment of theapparatus of the present invention;

FIG. 4 is a fragmentary side view of the preferred embodiment of theapparatus of the present invention illustrating the proximal nailsection thereof;

FIG. 5 is a longitudinal sectional view of the preferred embodiment ofthe apparatus of the present invention illustrating the proximal nailsection thereof;

FIG. 6 is an end view of the proximal nail section of FIGS. 4 and 5;

FIG. 7 is another end view of the proximal nail section of FIGS. 4 and5;

FIG. 8 is a side view of the preferred embodiment of the apparatus ofthe present invention illustrating the central nail section thereof;

FIG. 9 is a fragmentary perspective view of the central nail section ofFIG. 8;

FIG. 10 is a sectional view taken along lines 10of FIG. 8;

FIG. 11 is a fragmentary sectional side view of the preferred embodimentof the apparatus of the present invention illustrating the distal nailsection thereof;

FIG. 12 is a fragmentary perspective view of the distal nail section ofFIG. 11;

FIG. 13 is a fragmentary sectional view of the central nail section ofFIG. 8; and

FIG. 14 is a perspective fragmentary view of the instrumentation portionof the apparatus of the present invention showing the entry portal toolportion thereof;

FIG. 15 is a side fragmentary view of the instrumentation portion of theapparatus of the present invention illustrating the cannulatedobturator;

FIG. 16 is a sectional view taken along lines 16--16 of FIG. 15;

FIG. 17 is a sectional view taken along lines 17--17 of FIG. 15;

FIG. 18 is an elevational view of the reaming sheath portion of theinstrumentation used to install the preferred embodiment of theapparatus of the present invention;

FIG. 19 is another elevational view of the reaming sheath portion of theinstrumentation as used to install the intramedullary nail of thepresent invention;

FIG. 20 is a top view of the reaming sheath portion of theinstrumentation as used to install the intramedullary nail of thepresent invention;

FIG. 21 is a perspective view of the modular drill guide portion of theinstrumentation used to install the modular intramedullary nail of thepresent invention;

FIG. 22 is a fragmentary view illustrating a portion of the modulardrill guide of FIG. 21; and

FIGS. 23-25 are perspective views illustrating the surgical method stepsof implanting the modular intramedullary nail of the present inventionusing the instrumentation of FIGS. 14-22.

DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

FIGS. 1-3 illustrate the preferred embodiment of the apparatus of thepresent invention illustrated generally by the numeral 10. Modularintramedullary 10 includes three sections that are connectableend-to-end. The three sections include proximal nail section 11, centralnail section 12, and distal nail section 13. The three sections aresecured together using cannulated fastener 14.

In FIG. 1, cannulated fastener 14 includes an enlarged head 15, anelongated cylindrical hollow shaft 16, and a threaded distal end portion18 having external threads 19 thereon. Fastener 14 has a continuous openended cylindrically-shaped bore 17 that extends its full length.

Proximal nail section 11 includes a proximal end portion 20 that carriesa pair of circumferentially spaced apart slots 21. The slots 21 canreceive an insertion tool such as, for example, a drill guide, attachedusing slots and a bolt (not shown) that communicates with an internallythreaded section 23 of open ended longitudinal bore 22.

Bore 22 is intersected at an acute angle (approximately forty-fivedegrees (45°) for example) by a passageway that is defined by alignedpairs of diagonal openings 24 as shown in FIG. 5. Openings 24 canreceive bone screws (not shown). Bone screws can be inserted in onedirection for using the nail in the femoral mode and by inserting screwsin the opposite direction the nail can be used in the reconstructivemode.

Distal end portion 26 of proximal nail section 11 includes a conicalsection 27 for forming a taper lock connection with central nail section12. In order to prevent rotation between the sections 11, 12, a tooledflat surface 28 is formed on the distal end 26 of proximal nail section11 at conical socket 27. A similar tooled flat surface is provided onthe proximal end of central section 12. When the proximal 11 and central12 sections are assembled together, the corresponding tooled flatsurfaces 28, 33 abut and align to define a self-orienting, anti-rotationconnection between adjoining nail sections 11, 12.

In FIGS. 8-9, central nail section 12 is shown. Central nail section 12includes proximal end 29, distal end, and can have longitudinal flatexternal surfaces 37 (see FIGS. 8 and 10). Proximal end 29 includes aconical projection 31 for communicating with the socket 27 of proximalnail section 11. A tooled flat surface 33 on conical projection 31cooperates with the tooled flat surface 28 of conical socket section 27upon assembly of proximal 11 and central 12 nail sections.

The corresponding tooled flat surfaces 28, 33 insure that nail sections11, 12, do not rotate with respect to one another. Further, these tooledflat surfaces 28, 33 align and abut upon assembly so that the degree ofanteversion of the nail sections 11, 12 is preset prior to surgicalinsertion. The tooled flat surfaces 28, 33 define a self-orientingstructure when the nail sections 11, 12 are assembled. The conicalsurfaces 27, 31 define a locking taper connection that locks the twonail sections 11, 12 together upon assembly. Proximal end 29 can have anannular collar 36 that provides a gripping surface during disassembly.

The distal end 30 of central nail section 12 provides a conical socket32 for receiving distal end section 13. Conical socket 32 includes atooled flat surface 34 that cooperates with a similar and correspondingtooled flat surface on proximal end 38 of distal nail section 13.Central nail section 12 includes a longitudinal open ended bore 35 thatextends the full length of the nail section 12.

The central section 12 of the nail 10 preferably has a wall thicknessequal to nails that are clinically effective. Wall thickness is relatedto nail stiffness which affects the healing rate of the fractured bone.Manufacture of the taper requires a small inside diameter section of thenail to be present prior to machining the taper. Therefore the nailsection 12 is made with a larger outside diameter than will be required,allowing a large inside diameter with corresponding correct wallthickness. The end 30 of the nail section 12 that is to form the taperis swaged so the inside and outside diameter of the nail is reduced. Thetaper 32 is machined out of the swaged material. The nail section 12then has a taper 31, 32 on each end and a larger diameter in between.The central nail component has a wall thickness of between about 1.0 and2.0 mm. The central nail section preferably provides a pair of smallerdiameter bore sections at its opposing end portions. The nail componentsalso have a shaped projection 28 on the male connector section and ashaped socket on the female connector section. The central nailcomponent is about twice as long as, preferably at least twice as longas the proximal nail component. The central nail component is abouttwice as long as the distal nail component. In the preferred embodiment,the central component is between 125 and 300 mm in length. The threeassembled nail components provide an overall length of between 200 and500 mm in the preferred embodiment.

In FIG. 11, distal nail section 13 is shown. Distal nail section 13includes a proximal end 38 and a distal end 39. The proximal end portion38 has a conical projection 40 with a tooled flat surface 41 thereonthat corresponds to and registers against tooled flat surface 34 ofsocket 32 upon assembly of central nail section and distal nail section13. Lateral openings 42 extend transversely through distal nail section13. Similarly, lateral openings 43 extend transversely through distalnail section 13 at a position longitudinally spaced away from theopenings 42. Each of the openings 42, 43 communicates with longitudinalbore 44 that extends the full length of nail section 13. At the proximalend 38 of distal nail section 13, internally threaded section 45communicates with bore 44. Internally threaded section 45 has internalthreads that corresponds to the external threads 19 of cannulatedfastener 14. Upon assembly, the threads 19 engage the threads 45.

The enlarged head 15 of cannulated fastener 14 registers against annularshoulder 25 that defines an intersection between bore 22 and internalthreads 23 of proximal section 11, as shown in FIG. 5. Thus, uponassembly, the cannulated fastener 14 secures the three nail sections11-13 together, forming a taper lock or wedge lock connection betweenthe sections. Cannulated fastener 14 provides an internal bore 17 sothat a guide wire can be used to correctly channel placement of the nailsections 11-13 in a fractured bone. The cannulated fastener 14 holds thenail sections together when the nail sections are removed.

In FIGS. 14-22, instrumentation is shown that is used to install themodular intramedullary nail 10 of the present invention that isdisclosed in FIGS. 1-13. In FIG. 14, entry portal tool 50 is shownhaving a distal end 51 and a proximal end 52. The distal end 52 includesa bone engaging spike 53 that is placed upon the proximal end of thepatient's femur to begin surgical installation of the modularintramedullary nail 10. The proximal end has a handle 56.

Entry portal tool 50 has an elongated longitudinal bore 54 and alongitudinal slot 55 formed in the portal tool 50 as shown in FIG. 14.Handle 56 can be used by the surgeon to manipulate the entry portal tool50. The handle includes an elongated open ended bore 59 that holdselongated shaft 58 with wing nut 57 secured to one end thereof. Shaft 58slides in bore 59 and has an end 60 that extends to proximal end 52 ofentry portal tool 50. The shaft end 60 defines a stop for holdingcannulated obturator 70 and reaming sheath 62 in position after theyhave been assembled to entry portal tool 50. Suction port 61 is a flowchannel that extends to bore 54. The port 61 can be attached to aflexible hose or tubing and a suction machine for continuously movingblood that is generated during the operative procedure and receivedwithin the bore 68 of reaming sheath 62.

Reaming sheath 62 is an elongated cylindrically-shaped hollow sheathhaving a proximal end 63 and a distal end 64. The proximal end 63 has anannular collar 65 and includes a thickened flange 66 portion thatregisters with the slot 55 of entry portal tool 50 thus preventing anyrotation of sheath 62 when placed in bore 54 as occurs during use. Theflange 66 registers with slot 55 at proximal end 52, the location offlange 66 upon assembly being designed by the numeral 69 as the positionfor the flange. This positioning of flange 66 in slot 55 at 69 alignssuction port 67 with suction port 61.

In FIGS. 15-17, cannulated obturator 70 is shown, having a proximal endportion 71 and a distal end portion 72. Proximal end 71 is in the formof a cylindrical hub with openings therein like hubs 74, 75 of FIGS.16-17. Distal end 72 includes a conical tip 73. A pair of cylindricalperforated hubs 74, 75 are placed longitudinally between the proximal 71and distal 72 ends of cannulated obturator 70.

Each of the hubs 74, 75 and the conical tip 73 include correspondinglyplaced radially and circumferentially placed openings. The openings 77,78, 79 align along parallel lines that are parallel with the centrallongitudinal axis of cannulated obturator 70. This provides a matrix ofaligned guide openings that can be selected by the surgeon for placementof a guide wire therethrough.

During use, the surgeon places the reaming sheath 62 in entry portaltool 50 bore 54. The surgeon then places the cannulated obturator 70within the bore 68 of reaming sheath 62. The surgeon places the conicaltip 73 and bone spike 53 on the proximal femur and aligns the centrallongitudinal axis of reaming sheath 62 and cannulated obturator 70 withthe central longitudinal axis of the patient's intramedullary canal (SeeFIGS. 23-24). The surgeon can then place a guide wire (commerciallyavailable) through a selected set of aligned openings in the hubs 74, 75and conical tip 73. An aligned opening is also provided in proximal end71 of obturator 70.

It should be understood that when the surgeon places the guide wirethrough a selected set of the openings, the guide wire is maintained inparallel relationship with the central longitudinal axis of theobturator 70. Thus, a single guide wire extends through four alignedopenings and along a path parallel with the central longitudinal axis ofobturator 70. The four openings are respectively in proximal end portion71, hubs 74, 75 and conical tip 73. The surgeon can then thrust theguide wire up to a few inches into the femur and examine position of thewire fluoroscopically. If the guide wire position is unacceptable, thesurgeon then moves the guide wire radially and/or circumferentially afew millimeters to select a different set of aligned openings. Each timethe surgeon does select a different set of aligned openings, the guidewire is still maintained in parallel relationship with the tool bodybecause of the corresponding axial alignment of corresponding holes inthe conical tip 73, hubs 74, 75, and proximal end 71 of the obturator70. This allows the surgeon to move the guide wire circumferentially andradially to a desired position until the surgeon has chosen a suitablelocation for the guide wire. The guide wire defines the position of cutfor a cannulated drill reamer (commercially available) that tracks theguide wire once the obturator 70 is removed.

After the surgeon has selected a desirable location for the guide wire,the surgeon then removes obturator 70, leaving portal tool 50 andreaming sleeve 62. The surgeon then places a standard commerciallyavailable cannulated reamer over the guide wire and drills an openingthrough the femur that will accommodate modular intramedullary nail 10.

A plurality of longitudinal struts 76 connect conical end 73, hubs 74,75, and proximal end 71 of obturator 70. Longitudinal struts 76 arepositioned at the peripheral portion of obturator 70 so as not tointerfere with the surgeon's selection of aligned openings for placementof the guide wire during use.

In FIGS. 15-17, the plurality of radially and circumferentially spacedopenings in conical tip 73 are designated by the numeral 77. Theopenings in hub 74 (FIG. 16) are designated by the numeral 78. Theopenings in hub 75 (FIG. 17) are designated by the numerals 79.

In FIGS. 16 and 17, it can be seen that the openings 78 and 79 arecorrespondingly placed with reference to the central longitudinal axisof obturator 70 which represents the center openings 78a , 79arespectively of FIGS. 16 and 17. Each of the openings 77, 78, 79 are inthe same radial and circumferential position. The pattern of openings 77in conical tip 73 is the same as the patterns of openings 78, 79 inFIGS. 16-17, and the same pattern of openings is provided in proximalend 71. This insures that a guide wire inserted through any selected setof aligned openings in the cannulated obturator will always be parallelto the central longitudinal axis of the obturator 70.

FIGS. 21-22 show modular drill guide 80. Modular drill guide 80 includesa handle 81, recon drop 88, stem 87, hollow barrel 82, and a bore 83.Bore 83 is open ended for receiving an assembly bolt that will securemodular intramedullary nail 10 to barrel 82 at projections 84. Theprojections 84 are preferably spaced circumferentially about 180° apartand correspond to the slots 21 on the proximal end 20 of modularintramedullary nail 10 upon assembly. Using the bolt to engage threads23 of proximal nail component 11, and using slots 21 and projections 84for radial alignment, the central longitudinal axis of bore 83 alignswith the central longitudinal axis of nail 10 proximal section 11.

Once nail 10 is secured to barrel 82, the surgeon can then place theassembled nail 10 and its attached modular drill guide 80 through entryportal tool 50 (see FIG. 25). Before placement of the nail 10, obturator70 and reaming sleeve 62 are removed from bore 54 of entry portal tool50. Slot 55 defines an opening that can be occupied by modular drillguide 80 as shown in FIG. 24. Diagonal opening 85 in drill guide 80 canreceive a drill for forming a diagonal opening in the patient's bonetissue. The opening 85 and the projections 84 are positioned so that adrill tracking opening 85 will intersect one of the diagonal openings inthe proximal end of modular nail 10 for using the nail in the femoralmode.

The entry portal tool 50 allows precise placement of the guide rod withlittle interference from the muscles and is less sensitive to glancingoff the angled surface of the bone. The aligned holes of the obturator70 allow exact placement of the pin in the position required for properrecon nail placement. Use of the entry portal tool 50 can reduce initialtime to find the entry portal and secondary time later in surgery thatwould be required for screw placement.

Use of the entry portal tool 50 reduces the blood exposure to thesurgical team, reducing disease risk, and the blood may be collectedneatly and perhaps reinfused.

The following table lists the parts numbers and parts descriptions asused herein and in the drawings attached hereto.

    ______________________________________                                        PARTS LIST                                                                    Part Number     Description                                                   ______________________________________                                        10              modular intramedullary nail                                   11              proximal section                                              12              central section                                               13              distal section                                                14              cannulated fastener                                           15              head                                                          16              cylindrical hollow shaft                                      17              continuous open-ended bore                                    18              threaded distal end                                           19              external threads                                              20              proximal end                                                  21              slot                                                          22              open-ended longitudinal bore                                  23              internally threaded section                                   24              diagonal openings                                             25              annular shoulder                                              26              distal end                                                    27              conical socket section                                        28              tooled flat surface                                           29              proximal end                                                  30              distal end                                                    31              conical projection                                            32              conical socket                                                33              tooled flat surface                                           34              tooled flat surface                                           35              bore                                                          36              annular collar                                                37              longitudinal flat surface                                     38              proximal end                                                  39              distal end                                                    40              conical projection                                            41              tooled flat surface                                           42              lateral opening                                               43              lateral opening                                               44              longitudinal bore                                             45              internal threads                                              50              entry portal tool                                             51              distal end                                                    52              proximal end                                                  53              bone engaging spike                                           54              longitudinal bore                                             55              longitudinal slot                                             56              handle                                                        57              wing nut                                                      58              shaft                                                         59              bore                                                          60              shaft end                                                     62              reaming sheath                                                63              proximal end                                                  64              distal end                                                    65              annular collar                                                66              flange                                                        67              suction port                                                  68              longitudinal bore                                             69              flange location                                               70              cannulated obturator                                          71              proximal end                                                  72              distal end                                                    73              conical tip                                                   74              cylindrical perforated hub                                    75              cylindrical perforated hub                                    76              longitudinal strut                                            77              tip openings                                                  78              hub openings                                                   78a            center opening                                                79              hub openings                                                   79a            center opening                                                80              modular drill guide                                           81              handle                                                        82              barrel                                                        83              bore                                                          84              projections                                                   85              diagonal opening                                              86              opening                                                       87              stem                                                          88              recon drop                                                    89              opening                                                       90              opening                                                       F               femur                                                         ______________________________________                                    

The foregoing description should be considered exemplary of theinvention and not restrictive. It should also be understood thatimprovements and modifications can be made to the invention withoutdeparting from the spirit and scope of the invention as defined in theappended claims.

We claim:
 1. A modular intramedullary nail, comprising:a) a proximalnail component having an open ended longitudinal bore; b) a distal nailcomponent having an open ended longitudinal bore; c) a central nailcomponent having an open ended longitudinal bore and having proximal anddistal end portions that are respectively connected during use to theproximal and distal nail components, said central nail section borebeing of a generally uniform diameter along a majority of its length; d)connecting means for securing the proximal and distal nail components tothe proximal and distal end portions of the central nail component, theconnection means including corresponding conical socket and conicalprojecting end portions of adjoining nail components that can be fittedtogether and secured with force; and e) the connecting means includingself orienting means on the proximal add distal nail components adjacentthe respective conical socket and conical projecting end portions forresisting relative rotational movement between the components; f) acannulated fastener extending through a portion of the bore of theproximal and distal nail components, and through the entire length ofthe bore of the central nail component, the fastener having a proximalend portion with means thereon for gripping the proximal nail component,a distal end portion with external threads thereon, and an open endedlongitudinal bore; and g) the proximal end of the bore of the distalnail component having an internally threaded bore section that canthreadably engage the external threads of the cannulated fastener. 2.The modular nail of claim 1, wherein the central nail component has awall thickness of between about 1.0 and 2.0 millimeters along a majorityof its length.
 3. The modular nail of claim 1, wherein theself-orienting means includes corresponding tooled flat surfaces onadjacent and connecting conical socket and conical projecting portions.4. The modular nail of claim 1, wherein the proximal nail component hasa partially internally threaded bore section.
 5. The modular nail ofclaim 1, wherein the conical socket and conical projecting end portionsare generally frustro-conical in shape.
 6. The modular nail of claim 1,wherein said central nail component has an annular external collar atone end portion thereof.
 7. The modular nail of claim 1, wherein theself-orienting means includes at least one set of cooperating shapedflat surfaces.
 8. The modular nail of claim 7, wherein said at least oneset of shaped flat surfaces is formed on each conical projectingportion.
 9. The modular nail of claim 1, wherein the proximal nailcomponent has at least one transverse opening therethrough.
 10. Themodular nail of claim 1, wherein the distal nail component has at leastone transverse opening therethrough.
 11. The modular nail of claim 1,wherein the self orienting means includes a shaped at one end portionprojection on the male connector section and shaped socket on the femaleconnector section, the projection and socket being shaped to preventrelative rotational movement.
 12. The modular nail of claim 1, whereinthe distal nail component has a first and second end portion, the firstend portion having a conical projecting end portion, and the second endportion is frustroconically shaped.
 13. The modular nail of claim 1,wherein the central nail component is curved longitudinally.
 14. Themodular nail of claim 1, wherein the central nail component is abouttwice as long as the proximal nail component.
 15. The modular nail ofclaim 1, wherein the central nail component is at least twice as long asthe proximal nail component.
 16. The modular nail of claim 1, whereinthe central nail component is about twice as long as the distal nailcomponent.
 17. The modular nail of claim 1, wherein the central nailcomponent is at least twice as long as the distal nail component. 18.The modular nail of claim 1, wherein the central nail component isbetween 125 and 300 mm in length.
 19. The modular nail of claim 1,wherein the assembled nail components have an overall length of between200 and 500 mm.